A research team at the Institute for Neurosciences, led by Juan Lerma, has made significant strides in understanding the role of specific neurons in the amygdala in relation to anxiety and depression. Their findings, published in the journal iScience, reveal that restoring balance among neuronal excitability in a particular area of the amygdala can reverse behavioral changes associated with these conditions in mice.
The amygdala is known for its involvement in emotional processing, particularly anxiety and fear. Lerma's team focused on a distinct group of neurons whose activity levels were found to be imbalanced, potentially triggering pathological behaviors. Utilizing a genetically modified mouse model that overexpresses the Grik4 gene, which increases the production of GluK4-type glutamate receptors, they observed heightened neuronal excitability and behaviors akin to those seen in individuals with anxiety or social withdrawal, reminiscent of symptoms in autism or schizophrenia.
Through targeted corrections in the basolateral amygdala, the researchers normalized Grik4 expression, facilitating improved communication with inhibitory neurons in the centrolateral amygdala. This adjustment led to a reversal of anxiety-related behaviors, as demonstrated by various behavioral tests assessing anxiety, depression, and social interaction.
Moreover, the researchers expanded their approach to wild-type mice with naturally elevated anxiety levels, confirming that their findings may apply broadly beyond specific genetic models. However, some cognitive deficits, such as issues with object recognition memory, remained unaddressed, indicating the involvement of other brain regions like the hippocampus.
The implications of this study suggest promising therapeutic avenues for affective disorders, as targeting these neural circuits may provide a more focused treatment strategy. The research received support from multiple scientific institutions and funding programs in Spain.